EP0759105B2 - Verfahren zur herstellung von delignifizierten und gebleichten chemischen zellstoffen - Google Patents

Verfahren zur herstellung von delignifizierten und gebleichten chemischen zellstoffen Download PDF

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Publication number
EP0759105B2
EP0759105B2 EP95917403A EP95917403A EP0759105B2 EP 0759105 B2 EP0759105 B2 EP 0759105B2 EP 95917403 A EP95917403 A EP 95917403A EP 95917403 A EP95917403 A EP 95917403A EP 0759105 B2 EP0759105 B2 EP 0759105B2
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process according
treatment
weight
hydrogen peroxide
pressure
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French (fr)
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EP0759105A1 (de
EP0759105B1 (de
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Michel Devic
Jean-Pierre Schirmann
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Arkema France SA
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Atofina SA
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    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/1026—Other features in bleaching processes
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/1026—Other features in bleaching processes
    • D21C9/1042—Use of chelating agents
    • D—TEXTILES; PAPER
    • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
    • D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
    • D21C9/00—After-treatment of cellulose pulp, e.g. of wood pulp, or cotton linters ; Treatment of dilute or dewatered pulp or process improvement taking place after obtaining the raw cellulosic material and not provided for elsewhere
    • D21C9/10—Bleaching ; Apparatus therefor
    • D21C9/16—Bleaching ; Apparatus therefor with per compounds
    • D21C9/163—Bleaching ; Apparatus therefor with per compounds with peroxides

Definitions

  • the invention relates to a process for preparing delignified and bleached chemical paper pulp.
  • the chemical pastes obtained by cooking are subjected to several processing steps. delignifying and / or bleaching.
  • the first steps consist in perfecting the delignification resulting from cooking.
  • the next steps are bleaching steps.
  • the pasta After these delignifying and bleaching treatments, the pasta must usually have a whiteness at least 88-90 ° ISO and a very low kappa index while retaining good mechanical properties, ie without significant degradation of the cellulose. This degradation is detectable by measuring the viscosity of the dough or its degree of polymerization (DP).
  • DP degree of polymerization
  • the first significant steps are usually carried out by treatments with chlorine gas. or chlorine dioxide.
  • This article shows in particular the comparative delignification and bleaching powers of a series of reagents such as chlorine, chlorine dioxide, oxygen, ozone, hydrogen peroxide and also reports the results generally obtained in terms of kappa index, whiteness and viscosity,
  • oxygen alone has a capacity for delignification and not appreciably for bleaching.
  • Its chlorine replacement factor (CRF) is 5 and its use results in a reduction of about half of the kappa index (17 from 35), the viscosity obtained being 980 dm 3 / kg (about 37 cps ) and the whiteness of ISO 34 °.
  • the kappa index decreases by a little less than half (20 from 35), the viscosity obtained being 900 and more dm 3 / kg (about 30 cps, and the whiteness of 45 ° ISO; we obtain 91 ° ISO for a viscosity of around 600 and more dm 3 / kg.
  • Treatment with hydrogen peroxide makes it possible to whiten only pulps whose kappa index is less than 5 and whose manganese content is less than or equal to 3 ppm. and whose consistency is at least 25% by weight of dry matter relative to the total weight of the dough.
  • This treatment with H 2 O 2 is carried out at a claimed temperature between 50 and 140 ° C.
  • This manganese content less than or equal to 3 p.p.m. is obtained by a pretreatment with an acid or a complexing or sequestering agent in an acid medium.
  • the temperatures exemplified are 80, 90 and 120 ° C. At this temperature of 120 ° C does not correspond any indication of the pressure prevailing in the reaction medium.
  • This pressure could be the saturated water vapor pressure at the indicated temperature.
  • Examples 18 to 21 of EP0578304A1 using a chemical paste with a consistency of 30% show that the DP decreases from 1180 to 1030 when the final whiteness increases from 89.8 to 92.6 ° ISO.
  • Patent application EP0577157A2 describes a process for bleaching a dough having a consistency of 5 at 20%, with hydrogen peroxide in an alkaline medium, at a pressure of less than 25 bars and preferably less at 14 bars.
  • H 2 O 2 is carried out at the same room temperature as the ozone pretreatment.
  • patent application WO-A-93/14262 describes a process for bleaching a dough according to which the dough previously delignified, up to a Kappa index of less than 9.5, is pretreated with a complexing agent in the medium acid, then subjected to a bleaching step with hydrogen peroxide in the presence of a silicate and at a temperature less than 100 ° C.
  • the pressure at which the bleaching is carried out is not indicated.
  • Patent application WO-A-79/00861 describes a process for bleaching paper pulp according to which the pulp previously impregnated with chemicals undergoes treatment with hydrogen peroxide at a temperature between 100 and 150 ° C and at a differential pressure of 5 to 400 KPa of steam containing less than 1% oxygen. This document does not report the Kappa index of the paste before and after treatment.
  • the aim of the present invention is to provide a process for the preparation of delignified chemical paper pulps and bleached with a high DP, using oxygen and hydrogen peroxide as oxidizing agents and performing all steps. process treatment in reaction media at basic pH.
  • This process has also as an aim to avoid any step using a chlorinated derivative such as for example chlorine or chlorine dioxide and also avoid any step of treatment with other oxidizing agents including ozone or peracids.
  • This process makes it possible to prepare ECF and TCF pastes without using other oxidizing agents than oxygen and hydrogen peroxide.
  • Oxygen treatment (a) or oxygen delignification is now widely used in industry paper mill and in particular for the development of TCF and ECF doughs as indicated for example in the article by "Van Lierop, B, Oxygen delignification, Workshop on Emerging Pulping and Chlorine-free Technology, RALEIGH N.C., March 1-4, 1993) ".
  • step (a) of the process according to the invention are those known and used in the paper industry.
  • One or more pulp washing steps can be added at the end of the oxygen treatment in the medium of alkaline pH.
  • the oxygen treatment can also be carried out in several successive stages with oxygen, separated by washing steps.
  • the complexing or sequestering treatment (b) according to the present invention is carried out using a complexing agent or sequestering transition metals, such as for example DTPA, (Diethylenetriaminepentaacetate sodium), EDTA (sodium ethylenediaminetetraacetate), salts of phosphonic acids.
  • DTPA Diethylenetriaminepentaacetate sodium
  • EDTA sodium ethylenediaminetetraacetate
  • the amount of complexing or sequestering agent is from 0.1% to 1% by weight relative to the dry matter contained in the dough. Preferably this amount is from 0.25 to 0.5%.
  • the quantities of the products and reagents are always expressed in percent by weight relative to the weight of the dry matter of the dough or of the dough considered in the dry state.
  • the consistency of the dough is expressed in percent by weight of dry matter relative to the total weight of the dough.
  • Treatment b) is carried out in a medium having an alkaline pH.
  • the pH of the paste during the treatment b) is less than or equal to 12.5.
  • the pH in b) is from 8.5 to 9.5.
  • the alkaline pH during the treatment in b) is obtained either by the alkalinity residual pulp at the end of the oxygen treatment, either by the alkalinity of the complexing or sequestering agent, or again by the addition of a base, for example NaOH.
  • the manganese content of the pulp before the treatment with hydrogen peroxide c) does not exceed not 5 p.p.m. by weight relative to the weight of dry matter of this same paste.
  • the temperature of treatment b) is generally from 20 to 100 ° C and the preferred temperature from 60 to 90 ° C.
  • the duration of the treatment b) is generally from 1 to 30 minutes and preferably from 5 to 15 minutes.
  • the consistency of the dough during processing b) is generally 2 to 25% and the preferred consistency is from 4 to 12%.
  • the paste is washed with water. Washing is carried out according to known techniques from the paper industry with hot or cold water.
  • the kappa index of the paste before treatment with hydrogen peroxide does not exceed 17.
  • the process then makes it possible, in a final step P, to obtain a delignified paste and of high whiteness which can be used directly for papermaking.
  • the pressure p is from 5 to 200 bars absolute. This pressure range makes it possible to observe a advantage over maintaining a high DP when carrying out the method according to the invention.
  • the pressure p is from 25 to 50 bars absolute.
  • the alkali metal silicate is sodium silicate.
  • sodium silicate it is preferred for reasons of convenience, to use from 0.5 to 10% by weight of a commercial solution at 38 ° Bé relative to the weight of the dry matter, and better still from 4 to 8% in weight of this solution.
  • reaction temperature t is from 110 ° C to 180 ° C.
  • the preferred range of t is 130 ° C to 160 ° C.
  • the paste during the treatment with hydrogen peroxide, has a consistency of 4 to 35% by weight of dry matter relative to the total weight of the wet dough.
  • the process can be carried out effectively at low consistencies of approximately 4 to approximately 10% and the very fluid reaction medium can be easily displaced by pumping avoiding any clogging.
  • the consistency is 10 to 20%. This consistency range optimizes yield of the process.
  • the treatment with hydrogen peroxide has a duration of 1 minute to 3 hours. Duration varies in opposite direction of temperature increase.
  • the duration is from 15 minutes to 1 hour. These relatively short durations allow the increase of the hourly output of the manufacture of the delignified and bleached pulp.
  • hydrogen peroxide is used at a rate of 0.5 to 10% by weight relative to the weight of the dry matter of the dough.
  • step c) of delignification and bleaching according to the invention is carried out in a manner continuous or discontinuous (batch) using the devices generally used in the paper industry for the cooking the pasta and allowing the dough to be impregnated with the aqueous hydrogen peroxide solution and sodium silicate, at elevated pressure and temperature for the selected time. After this treatment c) the dough is decompressed, cooled and washed with water.
  • batch bleaching of high consistency dough (20 to 30%) can be done in the following way: next :
  • the dough is mixed cold with hydrogen peroxide and sodium silicate and water so as to obtain the chosen consistency, then introduced into a stainless steel autoclave so as to fill it as completely as possible possible. After closing the autoclave, a small amount of water is pumped until you get a pressure of ten bars and then the temperature is brought to the chosen temperature for the chosen time. During the temperature rise phase the expansion of the liquids causes an increase in pressure. This increase can be controlled by the flow of a little of the liquid phase during heating.
  • the DTPA pretreated paste is washed and mixed with hydrogen peroxide, silicate and water to have a consistency of 8 to 10% allowing the dough to be pumpable.
  • the mixture is then introduced under pressure, by a high pressure pump into the reactor via a heat exchanger which brings the mixture to the chosen temperature.
  • the length is calculated so as to ensure the duration of the selected bleaching, the bleached pulp is decompressed and cooled by dilution with water and then washed.
  • Ancillary devices such as heat exchangers and vapor recovery cyclones can be added to recover and enhance the heat and pressure of the dough after bleaching.
  • the present invention provides a new basic OQ sequence -P, step P being new in itself.
  • This sequence has technical advantages because in the techniques of the prior art it is necessary complexing or sequestering metals in an acid medium to be able to bleach to high degrees, hydrogen peroxide.
  • Patent application EP578304A shows that treatment in an acidic medium at controlled pH is necessary before you can perform the final step with hydrogen peroxide. All examples of EP578304 report a complexing treatment at acid pH or an acid wash at pH 5 before the final bleaching.
  • the present invention provides excellent results in terms of bleaching without requiring an acidic medium in step b) contrary to the general teaching of the prior art.
  • Step c) practiced according to the characteristics of the invention makes it possible, thanks to the use of a pressure p higher than the saturated steam pressure to avoid any significant evaporation of the liquid reagents.
  • the process according to the present invention therefore makes it possible to obtain almost complete delignification and bleaching. chemical pasta after cooking in just 3 steps and using only inexpensive oxidizing agents to namely oxygen and hydrogen peroxide.
  • Examples 1 to 46 which appear in Tables I to X were carried out using three original chemical pastes industrial obtained by kraft cooking and oxygen treatment.
  • the oxygen treatment of the pasta was carried out according to conventional conditions at 10% consistency, under an oxygen pressure of 3.5 bar, at a temperature of 95 ° C and for a period of 60 to 90 minutes depending on the nature of wood.
  • the paste chosen from Table A is suspended at 10% consistency with 0.5% DTPA (solution commercial at 40% by weight of sodium DTPA in water) and heated for 15 minutes (0.25 hours) at 90 ° C.
  • DTPA solution commercial at 40% by weight of sodium DTPA in water
  • the final pH is from 9 to 9.6 depending on the paste chosen.
  • the chosen paste is then filtered and washed with demineralized water
  • the paste collected in a) is mixed at room temperature with the charge of hydrogen peroxide, sodium silicate and demineralized water necessary to obtain the consistency chosen for the test, then the reaction medium thus obtained is placed in a autoclave in stainless steel which is completely filled with dough, reducing the dead space as much as possible. A few cm 3 of demineralized water are pumped into the autoclave to reach the chosen pressure. The autoclave is then heated to temperature t for the duration chosen.
  • Heating has the effect of increasing the internal pressure.
  • the autoclave closing valve is intermittently opened to allow a few cm 3 of liquid to escape.
  • the paste is collected on a filter and washed with demineralized water. The whiteness, the kappa index and the DP are then measured according to the ISO standards of the paper industry, mentioned above.
  • Table I shows tests 1, 2, 3, 4 and 5 carried out on the KFI dough.
  • Table II shows tests 6, 7, 8, 9, 11, 10, 12 and 13 carried out on the KFII paste.
  • Curve 2 for example shows that for a temperature of 150 ° C and at 25 bars the addition of 2% silicate earns 10 ISO whiteness points.
  • test 1 comparative 0% silicate
  • test 4 8% silicate
  • Table III shows the tests 14, 15, 16, 17, 18, 19, 4, 20, 21, carried out on the KFI dough.
  • Tables IV and X show tests 13, 22, 23, 24, 25, 26, 27, 45 and 46 carried out on the KFII paste.
  • Curves 5 and 6 also show that for the same dough and for otherwise identical conditions, an increase in temperature increases the whiteness.
  • Table V shows the tests 28, 4, 29, 30 carried out on the KFI dough.
  • Table VI shows the tests carried out on the KFII paste (tests 31, 32, 33, 34, 35).
  • Table VII shows tests carried out on the KFI paste (tests 36, 37, 20, 38).
  • Table VIII shows tests carried out on the KFI paste (tests 39, 21, 40, 2, 41, 45, 46).
  • Comparative test 39 of Table VIII carried out at atmospheric pressure and at low temperature (90 ° C.) leads to a much lower whiteness (79.2 ° ISO) than that obtained with the same quantities of reagents from test 31 (88.6 ° ISO).
  • Table IX shows the tests carried out on KR softwood kraft pulp with very low initial whiteness 34.5 ° ISO.
  • Test 44 shows that the conditions of the invention (temperature of 150 ° C., pressure of 100 bars, and 8% of silicate) make it possible to obtain a high whiteness (89.0 ° ISO), ie a gain of 54, 5 ° ISO and an almost complete delignification (kappa index equal to 1.2).
  • Test 43 shows that with 4% H 2 O 2 a gain of 43.8 ° ISO is still obtained.
  • Tests 23, 26 and 45 show that for the same paste, the efficiency of bleaching increases with temperature. At 170 ° C, a whiteness of ISO 88.3 ° is obtained in only 20 minutes of heating.

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  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Wood Science & Technology (AREA)
  • Paper (AREA)
  • Polysaccharides And Polysaccharide Derivatives (AREA)

Claims (19)

  1. Verfahren zur Herstellung einer delignifizierten und gebleichten chemischen Papiermasse (Zellstoffmasse), dem zufolge man eine durch Kochen erhaltene Holzzellulosemasse der folgenden Behandlungsabfolge unterwirft:
    a) Behandlung zur Entfernung des Lignins (Delignifizierungsbehandlung) mittels Sauerstoff, dann
    b) Behandlung mit einem Komplexierungsreagenz oder Chelatbildner (Maskierungsreagenz) für Übergangsmetalle mit nachfolgendem Waschschritt; anschließend
    c) Behandlung mittels Wasserstoffperoxid in Gegenwart eines Alkalimetallsilikats;
    dadurch gekennzeichnet, daß die Wasserstoffperoxidbehandlung bei einer Temperatur t von mehr als 100 °C und bei einem Druck p von mehr als dem 1,5fachen des Sättigungsdampfdrucks von Wasser bei der Temperatur t durchgeführt wird, und daß alle Behandlungsschritte des Verfahrens in einem Reaktionsmilieu mit basischem pH-Wert durchgeführt werden.
  2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß der alkalische pH-Wert der Zellstoffmasse während des Behandlungsschrittes b) weniger oder gleich 12,5 beträgt.
  3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, daß der alkalische pH-Wert der Zellstoffmasse während des Behandlungsschrittes b) 8,5 bis 9,5 beträgt.
  4. Verfahren nach einem der Ansprüche 1 bis 3, dadurch gekennzeichnet, daß der Komplex- oder Chelatbildner DTPA ist.
  5. Verfahren nach einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß der Komplex- oder Chelatbildner bei der Behandlung b) in einer Menge von 0,1 bis 1 Gew.-% eingesetzt wird, bezogen auf das Trockengewicht der auf diese Weise behandelten Papiermasse.
  6. Verfahren nach Anspruch 5, dadurch gekennzeichnet, daß die Menge 0,25 bis 0,5 Gew.-% beträgt.
  7. Verfahren nach einem der Ansprüche 1 bis 6, dadurch gekennzeichnet, daß der Mangangehalt der Zellstoffmasse vor der Wasserstoffperoxidbehandlung nicht 5 ppm (gewichtsbezogen) übersteigt, bezogen auf das Trockengewicht.
  8. Verfahren nach einem der Ansprüche 1 bis 7, dadurch gekennzeichnet, daß der Druck p 5 bis 200 bar absolut beträgt.
  9. Verfahren nach Anspruch 8, dadurch gekennzeichnet, daß der Druck p 25 bis 50 bar absolut beträgt.
  10. Verfahren nach einem der Ansprüche 1 bis 9, dadurch gekennzeichnet, daß das Alkalimetallsilikat Natriumsilikat ist.
  11. Verfahren nach Anspruch 10, dadurch gekennzeichnet, daß das Natriumsilikat in Form einer 0,5- bis 10gew.-%igen wäßrigen Lösung mit 38° Baumé hinzugegeben wird, bezogen auf das Trockengewicht.
  12. Verfahren nach Anspruch 11, dadurch gekennzeichnet, daß der Gewichtsgehalt der wäßrigen Lösung mit 38 Baumé-Grad 4 bis 8 Gew.-% beträgt, bezogen auf das Trockengewicht.
  13. Verfahren nach einem der Ansprüche 1 bis 12, dadurch gekennzeichnet, daß die Temperatur t 110 ° bis 180 °C beträgt.
  14. Verfahren nach Anspruch 13, dadurch gekennzeichnet, daß die Temperatur t 130 °C bis 160 °C beträgt.
  15. Verfahren nach einem der Ansprüche 1 bis 14, dadurch gekennzeichnet, daß die Zellstoffmasse bei der Wasserstoffperoxidbehandlung eine Konsistenz von 4 bis 35 Gew.-% aufweist, bezogen auf das Trockengewicht.
  16. Verfahren nach Anspruch 15, dadurch gekennzeichnet, daß die Konsistenz 10 bis 20 Gew.-% Trockenmaterial beträgt.
  17. Verfahren nach einem der Ansprüche 1 bis 16, dadurch gekennzeichnet, daß die Wasserstoffperoxidbehandlung 1 Minute bis 3 Stunden dauert.
  18. Verfahren nach Anspruch 17, dadurch gekennzeichnet, daß die Dauer 15 Minuten bis 1 Stunde beträgt.
  19. Verfahren nach einem der Ansprüche 1 bis 18, dadurch gekennzeichnet, daß das Wasserstoffperoxid in Mengen von 0,5 bis 10 Gew.-% eingesetzt wird, bezogen auf das Trockengewicht.
EP95917403A 1994-05-11 1995-04-14 Verfahren zur herstellung von delignifizierten und gebleichten chemischen zellstoffen Expired - Lifetime EP0759105B2 (de)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9405815A FR2719854B1 (fr) 1994-05-11 1994-05-11 Procédé de préparation de pâtes à papier chimiques délignifiées et blanchies.
FR9405815 1994-05-11
PCT/FR1995/000494 WO1995031599A1 (fr) 1994-05-11 1995-04-14 Procede de preparation de pates a papier chimiques delignifiees et blanchies

Publications (3)

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EP0759105A1 EP0759105A1 (de) 1997-02-26
EP0759105B1 EP0759105B1 (de) 1998-12-02
EP0759105B2 true EP0759105B2 (de) 2001-10-10

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EP95917403A Expired - Lifetime EP0759105B2 (de) 1994-05-11 1995-04-14 Verfahren zur herstellung von delignifizierten und gebleichten chemischen zellstoffen

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US (1) US6019870A (de)
EP (1) EP0759105B2 (de)
CN (1) CN1065304C (de)
AU (1) AU2348495A (de)
CA (1) CA2189796C (de)
ES (1) ES2126278T5 (de)
FI (1) FI117394B (de)
FR (1) FR2719854B1 (de)
NO (1) NO320946B1 (de)
WO (1) WO1995031599A1 (de)

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FR2747407B1 (fr) * 1996-04-12 1998-05-07 Atochem Elf Sa Procede de delignification et de blanchiment de pates a papier chimiques
CA2327248A1 (en) * 1999-12-02 2001-06-02 Andritz-Ahlstrom Inc. Environmentally-friendly fiberline for producing bleached chemical pulp
AU2001256024A1 (en) * 2000-05-04 2001-11-12 University Of New Brunswick Peroxide bleaching of wood pulp
US7001484B2 (en) 2000-05-04 2006-02-21 University Of New Brunswick Peroxide bleaching of wood pulp using stabilizers and sodium hydrosulfide reducing agent
US20050087315A1 (en) * 2003-10-28 2005-04-28 Donovan Joseph R. Low consistency oxygen delignification process
WO2009154898A1 (en) 2008-06-20 2009-12-23 International Paper Company Composition and recording sheet with improved optical properties
CN102926254B (zh) * 2012-11-18 2018-02-27 天津容业达科技发展有限公司 常压低温清洁制浆过程中添加的制浆助剂
US9365525B2 (en) 2013-02-11 2016-06-14 American Science And Technology Corporation System and method for extraction of chemicals from lignocellulosic materials
CN104088187A (zh) * 2014-06-05 2014-10-08 华南理工大学 一种纸浆漂白方法
US9382283B2 (en) 2014-08-01 2016-07-05 American Science And Technology Corporation Oxygen assisted organosolv process, system and method for delignification of lignocellulosic materials and lignin recovery
US9950858B2 (en) 2015-01-16 2018-04-24 R.J. Reynolds Tobacco Company Tobacco-derived cellulose material and products formed thereof
US11154087B2 (en) 2016-02-02 2021-10-26 R.J. Reynolds Tobacco Company Method for preparing flavorful compounds isolated from black liquor and products incorporating the flavorful compounds
US10196778B2 (en) 2017-03-20 2019-02-05 R.J. Reynolds Tobacco Company Tobacco-derived nanocellulose material
CN110644270B (zh) * 2019-08-27 2022-01-07 齐鲁工业大学 一种杨木kp浆tcf漂白生产溶解浆的工艺

Citations (1)

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Publication number Priority date Publication date Assignee Title
EP0402335A2 (de) † 1989-06-06 1990-12-12 Eka Nobel Ab Verfahren zum Bleichen von Lignocellulose enthaltenden Zellstoffen

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Publication number Priority date Publication date Assignee Title
EP0402335A2 (de) † 1989-06-06 1990-12-12 Eka Nobel Ab Verfahren zum Bleichen von Lignocellulose enthaltenden Zellstoffen

Non-Patent Citations (1)

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Title
D.H. Andrews et R.P. Singh, "Peroxide Bleaching" in "The Bleaching of Pulp", 3ème édition, TAPPI PRESS (1979), pages 211, 212, 240, 252, 253 †

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FR2719854B1 (fr) 1996-06-21
FR2719854A1 (fr) 1995-11-17
CN1147841A (zh) 1997-04-16
NO964609L (no) 1996-10-31
CA2189796C (fr) 2000-08-22
FI964499L (fi) 1996-11-08
US6019870A (en) 2000-02-01
ES2126278T3 (es) 1999-03-16
EP0759105A1 (de) 1997-02-26
CA2189796A1 (fr) 1995-11-23
CN1065304C (zh) 2001-05-02
FI117394B (fi) 2006-09-29
ES2126278T5 (es) 2002-02-16
WO1995031599A1 (fr) 1995-11-23
EP0759105B1 (de) 1998-12-02
NO964609D0 (no) 1996-10-31
AU2348495A (en) 1995-12-05
NO320946B1 (no) 2006-02-20
FI964499A0 (fi) 1996-11-08

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